The present invention relates to a normalizer for linear welds in continuous lengths of pipe, and more particularly relates to a normalizer which can, during operation, travel along beside a length of pipe produced from a mobile pipe mill such as that described for example in Vasar U.S. Pat. No. 3,014,118 issued Dec. 19, 1961 or my copending U.S. patent application Ser. Nos. 647,179 and 647,180.
After electrical resistance welding of pipe, it is necessary to reheat the forged weld to approximately 1500.degree. F. to 1950.degree. F., depending on the steel chemistry and allow that weld then to cool in air. This permits the grain structure to be properly refined. This is a requirement of most codes such as A.P.I. and C.S.A.
In stationary mills, this normalizing process is carried out by a normalizer inductor bar which is lowered onto the pipe as the pipe passes beneath it. Induction current through the bar heats the pipe which is then allowed to cool in the subsequent sizing section of the mill, usually assisted by a water quench. For best results, the weld zone is usually cooled to room temperature before normalizing takes place. This is not always practical in a stationary mill setup. As well, when the induction bar is lowered and raised, often the leading and trailing edges of the weld seam to be normalized are missed. Another problem often found in such normalizers is that the weld seam may become imperfectly aligned with respect to the induction bar as a long continuous length of metal pipe is formed. In such a case the seam may become offset with respect to the induction bar, reducing the efficiency of the normalizing operation.